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University of Bonn
Zentrum für Zahn-, Mund,- und Kieferheilkunde
Ahmad Alobeid

Ahmad Alobeid
Dr.med.dent, DDS, MS, EBO
University of Bonn

About

Publications

15,035

Reads

Citations

Skills and Expertise

Titanium

Stainless Steel

Mechanical Properties

Alloys

Friction

Material Characterization

Orthodontic Appliances

Zentrum für Zahn-, Mund,- und Kieferheilkunde
Bonn, Germany

Christoph Bourauel's Lab

Publications

Unilateral upper central incisor space closure using palatal mini-implants

Article

Feb 2022

Closure of a Unilateral Maxillary Central Incisor Space Using Palatal Mini- Implants

Preprint

Full-text available

May 2020

This case report (Pre-print accepted case report in Journal of Clinical Orthodontics) describes the interdisciplinary approach to treatment of a 14-year-old male who lost his maxillary right central incisor due to trauma. He presented with a convex profile, end-to-end Class II molar relationships, mild crowding in both arches, 5mm overjet and 4mm o...

Comparison of force loss due to friction of different wire sizes and materials in conventional and new self-ligating orthodontic brackets during simulated canine retraction

Article

Feb 2019

Aims: The aim of this study was to compare force loss due to friction (Fr) during simulated canine retraction using different archwire dimensions and materials between conventional and new self-ligating brackets. Methods: The tested brackets were (1) conventional brackets (Victory series, GAC twin and FLI twin), (2) self-ligating brackets (Damon-Q,...

figure : A frasaco model integrated in the experimental set up with the respective bracket system to be tested. On the left: bukkal brackets of the type FLI®SL, on the right: lingual bracket system Incognito. The wires are engaged into the brackets and vertical and horizontal displacements of 2 mm of the central incisor are adjusted.

Data

Mar 2018

Supplemental-figure-1-A-frasaco-model-integrated-in-the-experimental-set-up-with-the

Data

Mar 2018

Comparison of the efficacy of tooth alignment among lingual and labial brackets: an in vitro study

Article

Mar 2018

Background/objective: The aim of this study was to evaluate the efficacy of tooth alignment with conventional and self-ligating labial and lingual orthodontic bracket systems. Materials/methods: We tested labial brackets (0.022′′ slot size) and lingual brackets (0.018′′ slot size). The labial brackets were: (i) regular twin brackets (GAC-Twin [Den...

Comparison of the efficacy of tooth alignment among lingual and labial brackets: An in-vitro study

Poster

Full-text available

Jun 2017

AIM: The aim of this study was to evaluate the efficacy of tooth alignment with different conventional and self-ligating lingual and labial brackets using the orthodontic measurement and simulation system. MATERIAL AND METHOD: The tested orthodontic brackets were of the 0.022-in slot size for labial and 0.018-in for lingual brackets and were as fol...

Supplemental figure 1: A frasaco model integrated in the experimental...

Comparison of the force levels among labial and lingual self-ligating and conventional brackets in simulated misaligned teeth

Article

Jan 2017

Background/objective: The aim of this study was to evaluate force levels exerted by levelling arch wires with labial and lingual conventional and self-ligating brackets. Materials/methods: The tested orthodontic brackets were of the 0.022-in slot size for labial and 0.018-in for lingual brackets and were as follows: 1. Labial brackets: (i) conventi...

Fig. 1 Three-point bending test according to DIN EN ISO 15841 [10] in...

Fig. 2 Four-point bending test in the OMSS. The test geometry and free...

Fig. 3 Three-point bending test employing different brackets. The...

Fig. 4 Force/deflection diagrams in three-point bending. The wire types...

Fig 5 b Force/deflection diagrams in biomechanical testing with three...

Mechanical properties of different esthetic and conventional orthodontic wires in bending tests

Article

Dec 2016

Aims: The goal of this study was to determine the mechanical properties of different esthetic and conventional orthodontic wires in three-point and four-point bending tests, and in a biomechanical test employing three bracket systems. Methods: The behavior of round wires with a diameter of 0.46 mm (0.018") were investigated: uncoated nickel titaniu...

Fig. 3 Three-point bending test employing different brackets. The arrangement is such that a free wire length of 10 mm is ensured. The wire is deflected in intrusion and vestibular directions

Data

Dec 2016

Fig. 5 a Force/deflection diagrams in biomechanical testing with three brackets. The movement of the central bracket simulated an intrusion of up to 3.3 mm. Same notations as in Fig. 4. Again, two loading/unloading curves are displayed for each wire. The arrows indicate the loading and unloading branches. Obviously this sample of the composite wire showed a fracture at 2 mm deflection (marked by the circle) and the second loading cycle (2) runs with a clearly lower slope than the first one.

Data

Dec 2016

Fig. 4 Force/deflection diagrams in three-point bending. The wire types are labeled above each curve. As each sample was loaded twice, two loading/unloading curves are displayed for each wire. The arrows indicate the loading and unloading branches. Obviously this sample of the composite wire showed a fracture below 2 mm deflection (marked by the circle). Thus, the second loading cycle (2) runs with a clearly lower slope than the first one.

Data

Dec 2016

Fig. 5 b Force/deflection diagrams in biomechanical testing with three brackets, however, simulating a protrusion of up to 3.3 mm. Same notations as before. This composite wire did not fracture. The hysteresis curves of the NiTi wires are significantly reduced, compared to Figs. 4 and 5a. The elastic ligation seems to dominate the force/deflection behavior in this loading mode

Data

Dec 2016

Fig. 1 Three-point bending test according to DIN EN ISO 15841 in the OMSS. A wire segment of 30 mm is inserted and displaced to a maximum of 3.3 mm. The forces are registered upon unloading at predefined points

Data

Dec 2016

Fig. 6 Bar graphs of forces in three- and four-point bending and bending with different bracket arrangements at 1 mm (a) and 2 mm (b). Except for the translucent composite wire and the rematitan® wires in three-point bending, the forces are on a similar level. Minor differences exist, but do not seem to be clinically relevant

Data

Dec 2016

Fig. 2 Four-point bending test in the OMSS. The test geometry and free wire length is similar to the three-point bending from Fig. 1

Data

Dec 2016

Tab. 1 Compilation of the investigated arch wires and brackets together with manufacturer, material, order number, and short code for identification. All wires had a round cross section with a diameter of 0.46 mm (0.018")

Data

Dec 2016

Study of force loss due to friction comparing two ceramic brackets during sliding tooth movement

Article

Full-text available

Jul 2016

Objective To compare the percentage of force loss generated during canine sliding movements in newly introduced ceramic brackets with metal brackets. Materials and methods Two types of ceramic brackets, namely polycrystalline alumina (PCA) ceramic brackets (Clarity Advanced) and monocrystalline alumina (MCA) ceramic brackets (Inspire Ice) were comp...

Effectiveness of space closure by clear-aligners using two attachment types

Poster

Jun 2016

Objectives: To evaluate force levels produced by a series of Invisalign® aligners and to investigate the effectiveness of two types of attachments proposed by Align Technology to maximize tooth translation during space closure. Materials and methods: Ten randomly selected teeth (canines and premolars) were either fitted with either vertical attachm...

The Influence of Different Ligation Methods on the Friction between Brackets and Arch Wires

Poster

Full-text available

Jun 2016

Aim: The aim of this in-vitro study was to compare the percentage of force loss generated during canine sliding movement in combination with three types of ligatures in combination with conventional brackets (active steel, passive steel and elastomeric ligatures) as compared to two types of self-ligating brackets (active and passive). Material and...

Comparison of the force levels among labial and lingual self-ligating and conventional brackets in simulated misaligned teeth

Poster

Full-text available

Jun 2016

AIM: It was the aim of this study to evaluate force levels exerted by leveling arch wires with labial and lingual conventional and self-ligating brackets systems. MATERIALS AND METHODS: The tested orthodontic bracket systems were of the 0.022-in for labial and 0.018-in slot size for lingual brackets and were as follows: 1) Labial brackets: conventi...

Mechanical properties of aesthetic and nickel titanium arch wires with aesthetic and conventional brackets during initial stage of orthodontic treatment

Poster

Full-text available

Jun 2016

AIM: The aim of the study was to compare the force level at the initial phase of orthodontic treatment as well as force loss due to friction in simulated canine retraction of esthetic wires (glass-fiber-reinforced composite) compared with nickel titanium (NiTi) archwires with aesthetic and metal brackets. MATERIALS AND METHODS: The following materi...

Mechanische Eigenschaften ästhetischer und konventioneller kieferorthopädischer Drähte in unterschiedlichen Biegeversuchen

Research

Full-text available

Mar 2016

Ziel: Kieferorthopädische Patienten äußern immer häufiger die Bitte nach ästhetischen Drähten, die auch in wachsendem Umfang von verschiedenen Firmen angeboten werden. Dabei kommen auch unterschiedlichste Materialien und Beschichtungstechniken zum Einsatz. Ziel dieser Studie war, die mechanischen Eigenschaften verschiedener ästhetischer und konvent...

Materialeigenschaften von Kunststoffbögen im Vergleich zu NiTi-Bögen bei Einsatz ästhetischer und konventioneller Brackets

Conference Paper

Full-text available

Nov 2015

Die Zahl am Markt erhätlicher ästhetischer Bögen nimmt ständig zu. Häufig werden Beschichtungen aufgebracht, teils aber auch Bögen aus faserverstärkten Kunststoff angeboten. Ziel der Studie war, das Kraftniveau bei Nivellierung, die Kraft in Biegerversuchen und den Reibungsverlust bei bogengeführter Zahnbewegung von transluzenten Bögen mit denen...

Vergleich des Kraftniveaus selbstligierender und konventioneller Lingual- und Vestibulärbrackets bei kombinierter Zahnfehlstellung

Conference Paper

Full-text available

Nov 2015

Das Design selbstligierender Brackets hat einen entscheidenden Einfluss auf die Nivellierungseffektivität und unterliegt ständiger Weiterentwicklung. In dieser Studie wurde daher untersucht, inwiefern das Kraftniveaus verschiedener Nivellierungsbögen durch das Bracketsdesign sowohl in der Vestibulär- als auch in der Lingualtechnik beeinflusst wir...

Der Einfluss von Brackettyp und Ligatur auf das Reibungsverhalten bei der bogengeführten Zahnbewegung

Conference Paper

Full-text available

Nov 2015

Ziel: Bracketmaterial und -design, Bogenmaterial sowie die Art der Ligatur haben einen entscheidenden Einfluss auf das Reibungsverhalten bei einer bogengeführten Zahnbewegung. Ziel dieser Untersuchung war, die Reibung selbstligierender und konventioneller Brackets in Kombination mit verschiedenen Bögen und unterschiedlichen Ligaturen zu messen. Mat...

Mechanical properties of cobalt-chromium wires compared to stainless steel and β-titanium wires

Article

Full-text available

Nov 2014

Previous studies have reported on mechanical properties of different orthodontic wires. However, there is a paucity of information that comparing the mechanical properties of Blue Elgiloy (BE) when compared to stainless steel and TMA, as finishing wires as received by different companies. The aim of this study was to evaluate the mechanical propert...

Mechanische Eigenschaften ästhetischer und konventioneller kieferorthopädischer Drähte in unterschiedlichen Biegeversuchen

Conference Paper

Full-text available

Sep 2014

Reibung und Oberflächenrauheit von Stahldrähten bei bogengeführter Zahnbewegung mit konventionellen und selbstligierenden Brackets

Presentation

Full-text available

Sep 2014

Ziel: Vorangegangene Untersuchungen zeigten übereinstimmend, dass die Reibung bei bogengeführter Zahnbewegung mit dem Drahtquerschnitt ansteigt und insbesondere vom Drahtmaterial und der Oberflächenstruktur beeinflusst wird. Über die Zusammenhänge der Reibung mit der Ligierungsart, konventionell oder selbstligierend, besteht allerdings weiterhin Un...

Force Loss During Sliding Tooth Movement In Different Bracket/Wire Combinations

Conference Paper

Mar 2014

Objective: Previous studies reported that force loss during sliding mechanics varies between self-ligating (SL) and regular bracket system. Many clinicians use Nitinol; stainless steel (SS)or titanium Molybdenum alloy (TMA) during canine retraction or space closure. However there is no detailed information about force loss due to friction in differ...

Questions

When can be removed the fixed appliance after doing the finishing bending? Should we leave the fixed appliance passively!! How long?

Question

Jul 2016

When can be removed the fixed appliance after doing the finishing bending? Should we leave the fixed appliance passively!! How long? Is there any evidence please?